The present invention relates to a polarized signal receiver probe in general, and more particularly to a probe for detecting a polarized signal in a first waveguide and for launching the signal in a second waveguide disposed at right angle to the first waveguide.
Two linearly polarized signals, rotated 90.degree. from each other are used in satellite communications systems. The transmitted linearly polarized signals are received by way of a feed horn installed on the end, or forming part of, a circular waveguide, i.e. of circular cross-section. Only one of the two polarized signals is received, the other signal being reflected out of the feed horn. The detected signal is fed through a second waveguide, generally a rectangular waveguide, i.e. of rectangular cross-section whose axis is conventionally disposed at 90.degree. to the axis of the feed horn waveguide, and which feeds the detected signal to a low-noise amplifier.
Various arrangements may be used for receiving one of the polarized signals in the feed horn circular waveguide and for launching the detected signal into the rectangular waveguide, such as, for example, the probe disclosed in U.S. Pat. No. 4,414,516 comprising a receiver probe portion disposed in the circular waveguide, and a signal launch probe portion disposed in the rectangular waveguide, the probe being supported by a rotatable dielectric rod driven by a servomotor mounted on the waveguide assembly. The launch probe portion has its axis aligned with the axis of the circular waveguide and with the axis of the dielectric rod, such as to remain constantly perpendicular to the axis of the rectangular waveguide during rotation of the probe. The receiver probe portion has its longitudinal axis perpendicular to the axis of rotation such as to rotate between the two orthogonally polarized signals in the circular waveguide. By rotation to a desired position, one polarized signal is received and the other is reflected. The received signal is conducted by the transmission line portion of the probe through the rear wall of the circular waveguide and is launched into the rectangular waveguide by the launch probe portion.
The present invention is an improvement upon the prior art polarized signal receiver, transmission and launch probes.